Airborne rigid kite with on-board power plant for ship propulsion

ABSTRACT

A vehicle-based airborne wind turbine system having an aerial wing, a plurality of rotors each having a plurality of rotatable blades positioned on the aerial wing, an electrically conductive tether secured to the aerial wing and secured to a ground station positioned on a vehicle, wherein the aerial wing is adapted to receive electrical power from the vehicle that is delivered to the aerial wing through the electrically conductive tether; wherein the aerial wing is adapted to operate in a flying mode to harness wind energy to provide a first pulling force through the tether to pull the vehicle; and wherein the aerial wing is also adapted to operate in a powered flying mode wherein the rotors may be powered so that the turbine blades serve as thrust-generating propellers to provide a second pulling force through the tether to pull the vehicle.

This Application claims priority U.S. patent application Ser. No.14/485,412 entitled “Airborne Rigid Kite with On-Board Power Plant forShip Propulsion” filed Sep. 12, 2014 and claims priority to U.S.Provisional Patent Application No. 61/981,050 entitled “Airborne RigidKite With On-Board Power Plant For Ship Propulsion” filed on Apr. 17,2014, the contents of which is incorporated by reference in itsentirety.

BACKGROUND

Unless otherwise indicated herein, the materials described in thissection are not prior art to the claims in this application and are notadmitted to be prior art by inclusion in this section.

Power generation systems may convert chemical and/or mechanical energy(e.g., kinetic energy) to electrical energy for various applications,such as utility systems. As one example, a wind energy system mayconvert kinetic wind energy to electrical energy.

SUMMARY

A vehicle-based airborne wind turbine system capable of pulling a shipis provided. The system include an aerial wing having a plurality ofrotors each having rotatable blades positioned on the wing. The aerialwing is attached to a ground station positioned on the ship with anelectrically conductive tether. The aerial wing is adapted to operate ina flying mode where wind energy is harnessed by the wing during flightand a pulling force is directed through the tether to the ship. Theaerial wing is also adapted to operate in a powered flying mode wherethe rotors are powered to rotate the blades that serve asthrust-generating propellers to provide additional pulling force to pullthe ship. The aerial wing may also operate in a power generation modeduring the flying mode or powered flying mode where air moving acrossthe rotatable blades of one or more of the rotors forces them to rotate,thereby driving a generator to produce electrical energy.

In another aspect, a vehicle-based airborne wind turbine system isprovided having an aerial wing, a plurality of rotors each having aplurality of rotatable blades positioned on the aerial wing, anelectrically conductive secured to the aerial wing and to a groundstation positioned on a vehicle, wherein the aerial wing is adapted toreceive electrical power from the vehicle that is delivered through theelectrically conductive tether, wherein the aerial wing is adapted tooperate in a flying mode to harness wind energy to provide a firstpulling force through the tether to pull the vehicle, and wherein theaerial wing is also adapted to operate in a powered flying mode whereinthe rotors may be powered so that the turbine blades serve asthrust-generating propellers to provide a second pulling force throughthe tether to pull the vehicle.

In another aspect, an airborne wind turbine system is provided having anaerial wing, a plurality of rotors each having a plurality of rotatableblades positioned on the aerial wing, an electrically conductive tetherhaving a first end secured to the aerial wing and a second end securedto a ground station positionable on a vehicle, wherein the aerial wingis adapted to receive electrical power from the vehicle that isdelivered to the aerial wing through the electrically conductive tether,wherein the aerial wing is adapted to operate in a flying mode toharness wind energy to provide a first pulling force through the tetherto pull the vehicle, and wherein the aerial wing is also adapted tooperate in a powered flying mode wherein the rotors may be powered sothat the turbine blades serve as thrust-generating propellers to providea second pulling force through the tether to pull the vehicle.

In a further aspect, a method of pulling a vehicle is provided includingthe steps of providing an aerial wing, and a plurality of rotors eachhaving a plurality of rotatable blades positioned on the aerial wing,and having an electrically conductive tether having a first end securedto the aerial wing and a second end secured to a ground stationpositioned on a vehicle, wherein the aerial wing is adapted to receiveelectrical power from the vehicle that is delivered to the aerial wingthrough the electrically conductive tether; wherein the aerial wing isadapted to operate in a flying mode to harness wind energy to provide afirst pulling force through the tether to pull the vehicle; and whereinthe aerial wing is also adapted to operate in a powered flying modewherein the rotors are be powered so that the turbine blades serve asthrust-generating propellers to provide a second pulling force throughthe tether to pull the vehicle, and operating the aerial wing in thepowered flying mode to provide a pulling force through the tether topull the vehicle. In a further aspect, means for pulling a vehicle areprovided.

These as well as other aspects, advantages, and alternatives, willbecome apparent to those of ordinary skill in the art by reading thefollowing detailed description, with reference where appropriate to theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of airborne wind turbine 10 includingaerial vehicle 20 attached to a ship 1000 with an electricallyconductive tether 30, according to an example embodiment.

FIG. 2 is a close-up perspective view of the airborne wind turbine 10and aerial vehicle 20 shown in FIG. 1.

FIG. 3 is a close-up perspective view of the aerial vehicle 20 shown inFIGS. 1 and 2.

FIG. 4 is a simplified block diagram illustrating components of anairborne wind turbine, according to an example embodiment.

FIG. 5 is a side view of airborne wind turbine 10 with an aerial vehicle120 positioned on a perch 54, with an electrically conductive tether 30attaching the ship 1000 to aerial vehicle 120, according to an exampleembodiment.

FIG. 6 is a side view of airborne wind turbine 10 shown in FIG. 5, withthe aerial vehicle 120 unreeling from rotatable drum 53 positioned onship 1000, according to an example embodiment.

FIG. 7A is a top view of the perch platform 95 with tether 30 extendingfrom rotatable drum 53 with perch platform 95 in a first positionrelative to extending arm 58 of the perch platform 95, according to anexample embodiment.

FIG. 7B is a top view of the perch platform 95 shown in FIG. 7A withtether 30 extending from rotatable drum 53 with perch platform 95 in asecond position relative to extending arm 58 of the perch platform 95,according to an example embodiment.

FIG. 7C is a top view of the perch platform 95 shown in FIGS. 7A-7B withtether 30 extending from rotatable drum 53 with perch platform 95 in athird position relative to extendable arm 58 of the perch platform 95,according to an example embodiment.

FIG. 8A is a simplified illustration of an ocean-going vessel 300,according to an example embodiment.

FIG. 8B is an illustration showing an airborne wind turbine installed onan ocean-going vessel 300 and operating in a vessel-steering mode,according to an example embodiment.

FIG. 9 is a method of pulling a vehicle, according to an exampleembodiment.

FIG. 10 is a flowchart illustrating a process that may be implemented byone or more control systems on an ocean-going vessel, according to anexample embodiment.

DETAILED DESCRIPTION

Example methods and systems are described herein. Any example embodimentor feature described herein is not necessarily to be construed aspreferred or advantageous over other embodiments or features. Theexample embodiments described herein are not meant to be limiting. Itwill be readily understood that certain aspects of the disclosed systemsand methods can be arranged and combined in a wide variety of differentconfigurations, all of which are contemplated herein.

Furthermore, the particular arrangements shown in the Figures should notbe viewed as limiting. It should be understood that other embodimentsmay include more or less of each element shown in a given Figure.Further, some of the illustrated elements may be combined or omitted.Yet further, an example embodiment may include elements that are notillustrated in the Figures.

Overview

Ships have been used to transport products for centuries. Historically,ships were equipped with sails to harness wind energy to propel theship. More recently, wind powered ships have given way to large moderncargo ships propelled by underwater propellers driven by fuel poweredengines. The use of a traditional sail system on a modern cargo ship isoften not feasible due to the large physical size required for such asail system given that the propulsion requirements for a modern cargoship are often in the megawatt range. Additionally, the unpredictablenature of wind resources is often not attractive for cargo ships becauseallocated timeslots in ports often require strict adherence to scheduledarrival times. Thus, conventional sail systems to harness wind energyare not typically used with modern cargo ships.

Instead, modern cargo ships are typically propelled using one or moreunderwater propellers that are driven by a fuel powered engine. However,a typical modern cargo ship has the drawbacks of having high fuel costsand the potentially adverse environmental impact based on the use offossil fuels to provide ship propulsion.

The use of wind turbines as a means for harnessing energy has been usedfor a number of years. Conventional wind turbines typically includelarge turbine blades positioned atop a tower. An alternative to thecostly conventional wind turbine towers that may be used to harness windenergy is to use an aerial vehicle attached to a ground station with anelectrically conductive tether. Such an alternative may be referred toas an Airborne Wind Turbine or “AWT.”

An AWT is a wind based energy generation device that includes an aerialvehicle constructed of a rigid wing with mounted turbines that flies ina path, such as a substantially circular path, across the wind at, forexample, between 250 and 600 meters above the ground (or water) toconvert kinetic wind energy to electrical energy. The aerial vehicle isattached to a ground station via an electrically conductive tether. Inthe cross wind flight, the aerial vehicle may fly across the wind in acircular pattern similar to the tip of a wind turbine. The rotorsattached to the rigid wing may be used to generate power. In the powergenerating mode, air moving across the turbine blades forces them torotate, driving a generator to produce electricity. The aerial vehicleis typically connected to a ground station via an electricallyconductive tether that transmits power generated by the aerial vehicleto the ground station, where it may be used for various purposes,including powering the aerial vehicle or other auxiliary purposes.

The aerial vehicle may be parked on a perch positioned with the groundstation when not in use, for example during poor weather conditions. Insome embodiments, when parked, the aerial vehicle may be perched in anupward position with the axis of the fuselage positioned generallyperpendicular to the ground. When it is time to launch the aerialvehicle, the rotors may be operated in a thrust generating mode, wherethe rotors may be powered so that the turbine blades serve asthrust-generating propellers.

During launch, the aerial vehicle may operate in a hover mode, with thefuselage generally perpendicular to the ground (i.e., less than 45degrees away from vertical), the rotors may operate in the thrustgenerating mode, where the thrust-generating propellers power the aerialvehicle to a desired height. In some embodiments, the power to rotatethe turbine blades in the thrust generating mode is provided through theelectrically conductive tether from the ground station, and in otherembodiments the power to rotate the turbine blades is supplied frompower stored on the aerial vehicle.

When a desired height is attained, the aerial vehicle may transitionfrom a hover mode to a cross-wind flight or flying mode, and operate inthe power generation mode. During cross-wind flight, the aerial vehiclemay fly cross-wind in a substantially circular path. When it is desiredto land the aerial vehicle, such as during inclement weather, theelectrically conductive tether is wound onto a spool or drum in theground station and the aerial vehicle is reeled in towards a perch onthe ground station. Prior to landing on the perch, the aerial vehicletransitions from a flying mode to a hover mode. The drum is furtherrotated to further wind the tether onto the drum until the aerialvehicle eventually comes to rest on the perch.

A drum may be used to store the tether as it is reeled in towards theground station during a landing procedure. In an example embodiment, thedrum may rotate about a horizontal axis. The platform may include aperch that extends from the ground station and includes perch supports.In some embodiments, the perch and perch supports may rotate about thetop of the ground station to allow for a desired positioning of theperch during landing and launch.

Example embodiments are directed to an airborne wind turbine systempositioned on a cargo ship, or other seagoing vessel. It is known thatairborne wind turbines may fly at a distance of 500 meters above theground where the wind is significantly stronger than closer to theground (e.g. 70 meters). The wind at 500 meters may provide twice thepower as wind at 70 meters. Furthermore, strong, consistent winds may befound in offshore locations.

Example embodiments are directed to an airborne wind turbine system thatmay be positioned on the cargo ship or seagoing vessel where an aerialvehicle is attached by an electrically conductive tether that extendsfrom the aerial vehicle to a ground station located on the ship. Theaerial vehicle may be used to tow the cargo ship or other vessel byharnessing wind energy during cross wind flight and/or by propelling theaerial vehicle forward with its onboard propellers.

In particular, the present embodiments are directed to the use of arigid airborne, powered, tethered craft (referred to as an aerial winghereafter) for ship propulsion. The airborne wind turbine system may bethe same as that described above that is used on a ground-based airbornewind turbine system. The airborne wind turbine may include an aerialwing having an aerodynamic surface designed to be propelled by the windusing the crosswind principle in a flying mode, and a power plantmounted on the aerial wing consisting of rotors having propellers,electric motors and motor controllers. The power plant is capable ofboth generating thrust (thrust generating mode) to tow the ship and alsoof generating drag to generate electricity (power generating mode) thatmay be transferred to the ground station or stored on the aerial wingfor later use. The airborne turbine system may include an electricallyconductive cable or tether capable of transferring the generated tensionto an anchor point on the ship and capable of transferring electricpower to and from the power plant on the aerial vehicle. The airborneturbine system may also include an anchor point on the ship capable oftransferring the tether tension in the ship hull, as well as activeautonomous control which maintains the aerial wing on a predefined,stable trajectory.

When installed on a vessel, the following modes of operation may beused:

-   -   (a) Under good wind conditions, the aerial wing is propelled by        the wind during cross wind flight in a flying mode, thereby        generating tension in the tether and thereby pulling or towing        the ship forward.    -   (b) Under very favorable wind conditions, the onboard power        plant slows the aerial wing down by absorbing part of the wind        energy and operating in power generation mode while in flying        mode, or power generation mode. This mode of operation results        in pulling or towing power identical to (a) and the conversion        of wind energy to electrical energy which may be transferred        through the electrically conductive tether to the ship where it        may be used or stored on the vessel for either propulsive or        auxiliary purposes, or used or stored on the aerial wing for        either propulsive or auxiliary purposes.    -   (c) Under fair wind conditions, electric energy stored or        generated on the vessel (battery bank, main engine with        generator or auxiliary generator), or stored on the aerial wing,        can be delivered to the power plant on the aerial wing through        the electrically conductive tether to operate the aerial wing in        thrust generating mode while in the flying mode (hereinafter        referred to as powered flying mode). In this mode of operation,        the energy may be used to power the propellers on the aerial        vehicle, thereby providing an additional pulling force that        generates tension in addition to the pulling force as in (a).

As long as there is a component of the true wind speed in the traveldirection of the vessel, the net propulsive efficiency using thispowered flying mode is higher compared to a marine propeller referencingagainst water. Although electric energy is consumed in this mode, thepropulsive efficiency is significantly higher than using a marinepropeller. Under certain conditions, the net efficiency (electric powerin/propulsive power out) can be on the order of 200%-300%. This can beachieved because the system is still extracting energy from theavailable wind field while operating in the powered flying mode, thusthe pulling force of the harnessed wind from the flying mode is combinedwith the pulling force from the rotating blades of the rotors.

It will be appreciated that the powered flying mode of operation mayalso be used during many different types of wind conditions, includingthe fair, good, and very favorable conditions referred to above.Further, during the flying mode of operation, power may be supplied tothe rotors to provide for steering and control purposes.

In some embodiments, the aerial wing could have some rotors operating inpower generating mode, and others operating in powered flight mode, inwhich case the aerial wing may operate in both power generation mode andpowered flying mode at the same time.

Under unfavorable wind conditions, the aerial wing may be reeled in andperched or parked on the ground station.

The aerial wing embodiments provide significant advantages over anon-powered kite system. In particular, in non-powered kite systems,there is a narrow operating range. The propulsive power of the kitesystem is entirely dependent on the wind conditions (speed anddirection) and vessel velocity.

Furthermore, the system efficiency of a non-powered kite system drops asvessel velocity increases, and therefore the non-powered kite systemtechnology only makes sense for slow vessels and/or windy routes.Moreover, only wind-powered operation is possible, thus limiting thetechnology to a power-assisting system, which could not take the placeof marine propellers.

The present embodiments provide significant advantages over a flexiblekite system. Using a rigid structure for the aerial wing compared to aflexible kite allows an order of magnitude higher performance (pullingpower) per unit area of kite or aerial wing. In addition, using apowered aerial wing allows operation in the power generation mode and/orthe powered flying mode as described above.

The powered flying mode advantageously increases the range of winddirections in which the system can be used. Furthermore due to thepowered mode of operation, the system performance is less sensitive tovessel velocity compared to passive pulling only, i.e. such as providedby a non-powered flexible kite system. Moreover, because the presentembodiments may operate over a wider range of wind directions, theycould prove a cost-effective power-assist system for ships with powerrequirements ranging from kW's to MW's. In addition, they may also beuseful to serve as a backup propulsion system in the event of an enginefailure. When implemented, the present embodiments may lead tosignificant fuel savings and reduction in CO₂ emissions. In certainapplications, because the present embodiments can be powered, they couldactually replace the marine propeller(s) of a ship.

In addition, when the ship is docked, the airborne wind turbines mayalso be used to generate energy that may be used later for propulsion orother auxiliary purposes.

The present embodiments have been described with respect to use with awater-based vehicle such as a vessel or ship. However, the presentembodiments may also be used in connection with pulling land-basedvehicles such as trains, trucks, or buses, or even an aerial vehiclesuch as a balloon or blimp. For example, a blimp in the jetstream mayharvest energy from surrounding air, or vice versa. Therefore as usedherein the term “vehicle” includes water-based vehicles such as a vesselor ship, land-based vehicles such as a train, truck, or bus, as well asaerial vehicles such as a balloon or blimp.

Illustrative Vehicle-Based Airborne Wind Turbines

As disclosed in FIGS. 1-3, a vehicle-based airborne wind turbine system10 is disclosed, according to an example embodiment. The airborne windturbine system 10 is a wind based energy harnessing and energygeneration device that includes an aerial vehicle 20 constructed of arigid wing 22 with mounted turbines or rotors 40 a, 40 b that may fly ina path, such as a substantially circular path, across the wind. In anexample embodiment, the aerial vehicle 20 may fly between 250 and 600meters above the water to harness wind energy. However, an aerialvehicle may fly at other heights without departing from the scope of theinvention.

In the flying mode of operation during cross wind flight, wind energymay be harnessed by the surface of the wing 22 that is facing thedirection of the wind and a pulling force transmitted through the tether30 to pull the ship.

Advantageously, electrical energy stored or generated on the ship 1000can be delivered to the aerial wing 20 through the electricallyconductive tether to operate the aerial wing in thrust generating modewhile in the flying mode (powered flying mode). In some embodiments, theelectrical energy may come from a generator installed on the main engineof a normal transport ship. In other embodiments, power for the aerialwing comes from an auxiliary engine of the ship, reducing requiredenergy from the main engine, or comes from a water turbine used togenerate electricity due to the boat's forward velocity in the water. Inany event, in the powered flying mode, the energy may be used to powerthe blades 45 on the rotors 40 a-40 b on the aerial vehicle 20, suchthat the blades 45 serve to operate as thrust generating propellers,thereby providing a pulling force transferred through the tether 30 tothe ship 1000.

As long as there is a component of the true wind speed in the traveldirection of the vessel, the net propulsive efficiency using thispowered flying mode mode is higher compared to a marine propellerreferencing against water. Although electric energy is consumed in thismode, the propulsive efficiency is significantly higher than using amarine propeller. Under certain conditions, the net efficiency (electricpower in/propulsive power out) can be on the order of 200%-300%. Thiscan be achieved since the system is still extracting energy from theavailable wind field by harnessing energy in the same manner as in theflying mode, but also providing additional pulling force created by thepower of the rotating blades 45 on the rotors 40 a-40 b. The poweredflying mode of operation may be used on a boat where it is desired to berun at a constant spped to make port at a given time, as an example, orwhere speeds may be marginally increased or decreased according to windavailability.

In some embodiments, the power used to rotate the blades 45 of therotors 40 a-40 b on the aerial wing may be delivered from the ship 1000through the electrically conductive tether 30, and in other embodimentsit may be from energy stored on the aerial vehicle 20.

In a third mode of operation, during the flying mode, the aerial vehiclemay be operated in a power generation mode to convert kinetic windenergy to electrical energy. In the power generation mode of operation,the aerial vehicle 20 flies across the wind in a circular patternsimilar to the tip of a wind turbine. The rotors 40 a and 40 b attachedto the rigid wing 22 are used to generate power by slowing the wing 22down. Air moving across the turbine blades forces them to rotate,driving a generator to produce electrical energy. The aerial vehicle 20is connected to ship 1000 via an electrically conductive tether 30 thattransmits power generated by the aerial vehicle 20 to the ship 1000where it may be used for propulsive or auxiliary purposes. The energygenerated during power generation mode may also be stored on the aerialwing and later used to power the rotors or other auxiliary purposes.

As shown in FIG. 1, the aerial vehicle 20 may be connected to the tether30, and the tether 30 may be connected to a ground station 50. In thisexample, the tether 30 may be attached to the ground station at onelocation on the ground station 50, and attached to the aerial vehicle 20at three locations on the aerial vehicle 20 using bridle 32 a, 32 b, and32 c. However, in other examples, the tether 30 may be attached atdifferent locations on the ship 1000 or the aerial vehicle 20.

The ground station 50 may be used to hold and/or support the aerialvehicle 20 until it is in an operational mode. The ground station 50 mayinclude a vertically oriented main member 52 that may extend above thedeck 1010 of the ship 1000 on the order of 15 meters. However a mainmember is not required and the ground station could be located so thatthe end of the tether 30 extends into the hull of the ship to reduce themoment created when a main member 52 is extended above the deck 1010 ofthe ship 1000. The ground station 50 may also include a drum 53rotatable about drum axis 55 that is used to reel in aerial vehicle 20by winding the tether 30 onto the rotatable drum 53. In this example,the drum 53 is oriented horizontally, although the drum may also beoriented vertically (or at an angle). Further, the ground station 50 maybe further configured to receive the aerial vehicle 20 during a landing.For example, perch support members 56 a and 56 b are attached to perchpanel 54 and extend outwardly from rotatable drum 53. When the tether 30is wound onto drum 53 and the aerial vehicle 20 is reeled in towards theground station 50, the aerial vehicle 20 may come to rest upon perchpanel 54.

During power generation mode, the tether 30 may transmit electricalenergy generated by the aerial vehicle 20 to the ground station 50,which may then be used for propulsive or auxiliary purposes (e.g.,stored). In addition, the tether 30 may transmit electricity to theaerial vehicle 20 in order to power the aerial vehicle 20 duringtakeoff, landing, hover mode, powered flying mode or other purposes,such as aileron control. The tether 30 may be constructed in any formand using any material which may allow for the transmission, delivery,and/or harnessing of electrical energy generated by the aerial vehicle20 and/or transmission of electricity to the aerial vehicle 20. Thetether 30 may also be configured to withstand one or more forces of theaerial vehicle 20 when the aerial vehicle 20 is in an operational mode.For example, the tether 30 may include a core configured to withstandone or more forces of the aerial vehicle 20 when the aerial vehicle 20is in hover mode, flying mode, powered flying mode, or power generationmode. The core may be constructed of any high strength fibers or acarbon fiber rod. In some examples, the tether 30 may have a fixedlength and/or a variable length. For example, in one example, the tetherhas a fixed length of 500 meters.

The aerial vehicle 20 may include or take the form of various types ofdevices, such as a kite, a helicopter, a wing and/or an airplane, amongother possibilities. The aerial vehicle 20 may be formed of solidstructures of metal, plastic and/or other polymers. The aerial vehicle20 may be formed of any material which allows for a highthrust-to-weight ratio and generation of electrical energy which may beused in utility applications. Additionally, the materials may be chosento allow for a lightning hardened, redundant and/or fault tolerantdesign which may be capable of handling large and/or sudden shifts inwind speed and wind direction. Other materials may be possible as well.

As shown in FIG. 1, and in greater detail in FIGS. 2 and 3, the aerialvehicle 20 may include a main wing 22, rotors 40 a and 40 b, tail boomor fuselage 24, and tail wing 26. Any of these components may be shapedin any form which allows for the use of components of lift to resistgravity and/or move the aerial vehicle 20 forward.

The main wing 22 may provide a primary lift for the aerial vehicle 20.The main wing 22 may be one or more rigid or flexible airfoils, and mayinclude various control surfaces, such as winglets, flaps, rudders,elevators, etc. The control surfaces may be used to stabilize the aerialvehicle 20 and/or reduce drag on the aerial vehicle 20 during hovermode, flying mode, powered flying mode, and/or power generation mode.The main wing 22 may be any suitable material for the aerial vehicle 20to engage in the operational modes and, for example, the main wing 20may include carbon fiber and/or e-glass. Moreover, the main wing 22 mayhave a variety dimensions. For example, the main wing 22 may have one ormore dimensions that correspond with a conventional wind turbine blade.As another example, the main wing 22 may have a span of 8 meters, anarea of 4 meters squared, and an aspect ratio of 15.

Rotor connectors 43 may be used to connect the upper rotors 40 a to themain wing 22, and rotor connectors 41 may be used to connect the lowerrotors 40 b to the main wing 22. In some examples, the rotor connectors43 and 41 may take the form of or be similar in form to one or morepylons. In this example, the rotor connectors 43 and 41 are arrangedsuch that the upper rotors 40 b are positioned above the wing 22 and thelower rotors 40 a are positioned below the wing 22.

The rotors 40 a and 40 b may be configured to drive one or moregenerators for the purpose of generating electrical energy, such as inpower generation mode. In this example, the rotors 40 a and 40 b mayeach include one or more blades 45, such as three blades. The one ormore rotor blades 45 may rotate via interactions with the wind and whichcould be used to drive the one or more generators. In addition, therotors 40 a and 40 b may also be configured to provide a thrust to theaerial vehicle 20 during powered flying mode. With this arrangement, therotors 40 a and 40 b may function as one or more propulsion units, suchas a propeller. Although the rotors 40 a and 40 b are depicted as fourrotors in this example, in other examples the aerial vehicle 20 mayinclude any number of rotors, such as less than four rotors or more thanfour rotors, e.g. six or eight rotors.

Referring back to FIG. 1, when it is desired to land the aerial vehicle20, the drum 53 is rotated to reel in the aerial vehicle 20 towards theperch panel 54 on the ground station 50, and the electrically conductivetether 30 is wound onto drum 53. Prior to landing on the perch panel 54,the aerial vehicle 20 transitions from a flying mode to a hover mode.The drum 53 is further rotated to further wind the tether 30 onto thedrum 53 until the aerial vehicle 20 comes to rest on the perch panel 54.

Illustrative Examples of a Vehicle-Based Airborne Wind Turbine System

FIG. 4 is a simplified block diagram illustrating components of the AWT200, which may take the form of AWT shown in FIG. 3. In particular, theAWT 200 includes a ground station 210, a tether 220, and an aerialvehicle 230, which may take the form of aerial vehicle 20 in FIGS. 1-3,or aerial vehicle 120 shown in FIGS. 5 and 6. The ground station 210 maytake the form of or be similar in form to the ground station 50, thetether 220 may take the form of or be similar in form to the tether 30,and the aerial vehicle 230 may take the form of or be similar in form tothe aerial vehicle 20 shown in FIGS. 1-3, or aerial vehicle 120 shown inFIGS. 5 and 6.

As shown in FIG. 4, the ground station 210 may include one or moreprocessors 212, data storage 214, and program instructions 216. Aprocessor 212 may be a general-purpose processor or a special purposeprocessor (e.g., digital signal processors, application specificintegrated circuits, etc.). The one or more processors 212 can beconfigured to execute computer-readable program instructions 216 thatare stored in a data storage 214 and are executable to provide at leastpart of the functionality described herein.

The data storage 214 may include or take the form of one or morecomputer-readable storage media that may be read or accessed by at leastone processor 212. The one or more computer-readable storage media mayinclude volatile and/or non-volatile storage components, such asoptical, magnetic, organic or other memory or disc storage, which may beintegrated in whole or in part with at least one of the one or moreprocessors 212. In some embodiments, the data storage 214 may beimplemented using a single physical device (e.g., one optical, magnetic,organic or other memory or disc storage unit), while in otherembodiments, the data storage 214 can be implemented using two or morephysical devices.

As noted, the data storage 214 may include computer-readable programinstructions 216 and perhaps additional data, such as diagnostic data ofthe ground station 210. As such, the data storage 214 may includeprogram instructions to perform or facilitate some or all of thefunctionality described herein.

In a further respect, the ground station 210 may include a communicationsystem 218. The communications system 218 may include one or morewireless interfaces and/or one or more wireline interfaces, which allowthe ground station 210 to communicate via one or more networks. Suchwireless interfaces may provide for communication under one or morewireless communication protocols, such as Bluetooth, WiFi (e.g., an IEEE802.11 protocol), Long-Term Evolution (LTE), WiMAX (e.g., an IEEE 802.16standard), a radio-frequency ID (RFID) protocol, near-fieldcommunication (NFC), and/or other wireless communication protocols. Suchwireline interfaces may include an Ethernet interface, a UniversalSerial Bus (USB) interface, or similar interface to communicate via awire, a twisted pair of wires, a coaxial cable, an optical link, afiber-optic link, or other physical connection to a wireline network.The ground station 210 may communicate with the aerial vehicle 230,other ground stations, and/or other entities (e.g., a command center)via the communication system 218.

In an example embodiment, the ground station 210 may includecommunication systems 218 that may allow for both short-rangecommunication and long-range communication. For example, ground station210 may be configured for short-range communications using Bluetooth andmay be configured for long-range communications under a CDMA protocol.In such an embodiment, the ground station 210 may be configured tofunction as a “hot spot”; or in other words, as a gateway or proxybetween a remote support device (e.g., the tether 220, the aerialvehicle 230, and other ground stations) and one or more data networks,such as cellular network and/or the Internet. Configured as such, theground station 210 may facilitate data communications that the remotesupport device would otherwise be unable to perform by itself.

For example, the ground station 210 may provide a WiFi connection to theremote device, and serve as a proxy or gateway to a cellular serviceprovider's data network, which the ground station 210 might connect tounder an LTE or a 3G protocol, for instance. The ground station 210could also serve as a proxy or gateway to other ground stations or acommand station, which the remote device might not be able to otherwiseaccess.

Moreover, as shown in FIG. 2, the tether 220 may include transmissioncomponents 222 and a communication link 224. The transmission components222 may be configured to transmit electrical energy from the aerialvehicle 230 to the ground station 210 and/or transmit electrical energyfrom the ground station 210 to the aerial vehicle 230. The transmissioncomponents 222 may take various different forms in various differentembodiments. For example, the transmission components 222 may includeone or more conductors that are configured to transmit electricity. Andin at least one such example, the one or more conductors may includealuminum and/or any other material that may allow for the conduction ofelectric current. Moreover, in some implementations, the transmissioncomponents 222 may surround a core of the tether 220 (not shown).

The ground station 210 may communicate with the aerial vehicle 230 viathe communication link 224. The communication link 224 may bebidirectional and may include one or more wired and/or wirelessinterfaces. Also, there could be one or more routers, switches, and/orother devices or networks making up at least a part of the communicationlink 224.

Further, as shown in FIG. 2, the aerial vehicle 230 may include one ormore sensors 232, a power system 234, power generation/conversioncomponents 236, a communication system 238, one or more processors 242,data storage 244, and program instructions 246, and a control system248.

The sensors 232 could include various different sensors in variousdifferent embodiments. For example, the sensors 232 may include a globala global positioning system (GPS) receiver. The GPS receiver may beconfigured to provide data that is typical of well-known GPS systems(which may be referred to as a global navigation satellite system(GNNS)), such as the GPS coordinates of the aerial vehicle 230. Such GPSdata may be utilized by the AWT 200 to provide various functionsdescribed herein.

As another example, the sensors 232 may include one or more windsensors, such as one or more pitot tubes. The one or more wind sensorsmay be configured to detect apparent and/or relative wind. Such winddata may be utilized by the AWT 200 to provide various functionsdescribed herein.

Still as another example, the sensors 232 may include an inertialmeasurement unit (IMU). The IMU may include both an accelerometer and agyroscope, which may be used together to determine the orientation ofthe aerial vehicle 230. In particular, the accelerometer can measure theorientation of the aerial vehicle 230 with respect to earth, while thegyroscope measures the rate of rotation around an axis, such as acenterline of the aerial vehicle 230. IMUs are commercially available inlow-cost, low-power packages. For instance, the IMU may take the form ofor include a miniaturized MicroElectroMechanical System (MEMS) or aNanoElectroMechanical System (NEMS). Other types of IMUs may also beutilized. The IMU may include other sensors, in addition toaccelerometers and gyroscopes, which may help to better determineposition. Two examples of such sensors are magnetometers and pressuresensors. Other examples are also possible.

While an accelerometer and gyroscope may be effective at determining theorientation of the aerial vehicle 230, slight errors in measurement maycompound over time and result in a more significant error. However, anexample aerial vehicle 230 may be able mitigate or reduce such errors byusing a magnetometer to measure direction. One example of a magnetometeris a low-power, digital 3-axis magnetometer, which may be used torealize an orientation independent electronic compass for accurateheading information. However, other types of magnetometers may beutilized as well.

The aerial vehicle 230 may also include a pressure sensor or barometer,which can be used to determine the altitude of the aerial vehicle 230.Alternatively, other sensors, such as sonic altimeters or radaraltimeters, can be used to provide an indication of altitude, which mayhelp to improve the accuracy of and/or prevent drift of the IMU.

As noted, the aerial vehicle 230 may include the power system 234. Thepower system 234 could take various different forms in various differentembodiments. For example, the power system 234 may include one or morebatteries for providing power to the aerial vehicle 230. In someimplementations, the one or more batteries may be rechargeable and eachbattery may be recharged via a wired connection between the battery anda power supply and/or via a wireless charging system, such as aninductive charging system that applies an external time-varying magneticfield to an internal battery and/or charging system that uses energycollected from one or more solar panels.

As another example, the power system 234 may include one or more motorsor engines for providing power to the aerial vehicle 230. In someimplementations, the one or more motors or engines may be powered by afuel, such as a hydrocarbon-based fuel. And in such implementations, thefuel could be stored on the aerial vehicle 230 and delivered to the oneor more motors or engines via one or more fluid conduits, such aspiping. In some implementations, the power system 234 may be implementedin whole or in part on the ground station 210.

As noted, the aerial vehicle 230 may include the powergeneration/conversion components 236. The power generation/conversioncomponents 236 could take various different forms in various differentembodiments. For example, the power generation/conversion components 236may include one or more generators, such as high-speed, direct-drivegenerators. With this arrangement, the one or more generators may bedriven by one or more rotors, such as the rotors 40 a and 40 b. And inat least one such example, the one or more generators may operate atfull-rated-power wind speeds of 11.5 meters per second, at a capacityfactor which may exceed 60 percent. As such, the one or more generatorsmay generate electrical power from 40 kilowatts to 600 megawatts.

Moreover, as noted, the aerial vehicle 230 may include a communicationsystem 238. The communication system 238 may take the form of or besimilar in form to the communication system 218. The aerial vehicle 230may communicate with the ground station 210, other aerial vehicles,and/or other entities (e.g., a command center) via the communicationsystem 238.

In some implementations, the aerial vehicle 230 may be configured tofunction as a “hot spot”; or in other words, as a gateway or proxybetween a remote support device (e.g., the ground station 210, thetether 220, other aerial vehicles) and one or more data networks, suchas cellular network and/or the Internet. Configured as such, the aerialvehicle 230 may facilitate data communications that the remote supportdevice would otherwise be unable to perform by itself.

For example, the aerial vehicle 230 may provide a WiFi connection to theremote device, and serve as a proxy or gateway to a cellular serviceprovider's data network, which the aerial vehicle 230 might connect tounder an LTE or a 3G protocol, for instance. The aerial vehicle 230could also serve as a proxy or gateway to other aerial vehicles or acommand station, which the remote device might not be able to otherwiseaccess.

As noted, the aerial vehicle 230 may include the one or more processors242, the program instructions 244, and the data storage 246. The one ormore processors 242 can be configured to execute computer-readableprogram instructions 246 that are stored in the data storage 244 and areexecutable to provide at least part of the functionality describedherein. The one or more processors 242 may take the form of or besimilar in form to the one or more processors 212, the data storage 244may take the form of or be similar in form to the data storage 214, andthe program instructions 246 may take the form of or be similar in formto the program instructions 216.

Moreover, as noted, the aerial vehicle 230 may include the controlsystem 248. In some implementations, the control system 248 may beconfigured to perform one or more functions described herein. Thecontrol system 248 may be implemented with mechanical systems and/orwith hardware, firmware, and/or software. As one example, the controlsystem 248 may take the form of program instructions stored on anon-transitory computer readable medium and a processor that executesthe instructions. The control system 248 may be implemented in whole orin part on the aerial vehicle 230 and/or at least one entity remotelylocated from the aerial vehicle 230, such as the ground station 210.Generally, the manner in which the control system 248 is implemented mayvary, depending upon the particular application.

While the aerial vehicle 230 has been described above, it should beunderstood that the methods and systems described herein could involveany suitable aerial vehicle that is connected to a tether, such as thetether 230 and/or the tether 30.

FIGS. 5 and 6 show an example embodiment of vehicle-based airborne windturbine 10 that includes aerial vehicle 120 having a fuselage 124. InFIG. 5, aerial vehicle 120 is shown perched on perch panel 54 extendingfrom perch support 56 a attached to ground station 50. An electricallyconductive tether 30 is shown extending from rotatable drum 53 thatrotates about horizontal drum axis 55 to aerial vehicle 120. Therotatable drum 53 is positioned atop upper end 52 a of main verticalmember 52. An extending arm 58 extends from the top 52 a of main member52 to provide additional truss support to the main member 52.

FIG. 6 is a side view of the airborne wind turbine 10 shown in FIG. 5,with the aerial vehicle 120 unreeling from rotatable drum 53. Rotatabledrum 53 may be used to store the tether 30 as it is reeled in towardsthe ground station 50 during a landing procedure. In a one embodiment,the drum 53 may rotate about horizontal axis 55.

FIG. 7A is a top view of the perch platform 95 that may be used, withtether 30 extending from rotatable drum 53 with perch platform 95attached to perch supports 56 a and 56 b attached to perch panel 54 andperch bar 54 a in a first position relative to extending arm 58,according to an example embodiment.

FIG. 7B is a top view of the perch platform 95 shown in FIG. 7A withtether 30 extending from rotatable drum 53 with perch platform 95attached to perch supports 56 a and 56 b attached to perch panel 54 andperch bar 54 a in a second position relative to extending arm 58,according to an example embodiment.

FIG. 7C is a top view of the perch platform 50 shown in FIGS. 7A-7B withtether 30 extending from rotatable drum 53 with perch platform 95attached to perch support 56 a and 56 b attached to perch panel 54 andperch bar 54 a in a third position relative to extending arm 58,according to an example embodiment.

In the embodiments shown in FIGS. 7A-7C, perch platform 95, perchsupports 56 a and 56 b and perch panel 54 may rotate about the top 52 aof main element 52 to allow for a desired positioning of the perch panel54 during landing and launch.

It will be appreciated that the tether 30 must withstand significanttension forces. For example, the tension of the tether during crosswindflight may be 15 kilonewtons (KN), and even great during powered flyingmode. Tether 30 may be constructed of a carbon fiber core surrounded byaluminum conductors. The carbon fiber core and aluminum conductors maybe positioned within an outer insulation. In an example embodiment thatmay be used in the present embodiments, the diameter of the carbon fibercore is 14 millimeters and the diameter of the tether is 24 millimeters.

The positioning of the rotatable drum 53 and/or rotation of the perchplatform 95 may be used for purposes of steering or turning the ship1000. For example, the aerial wing 120 could fly in a directionperpendicular to the longitudinal axis of the ship 1000, and whenattached at the front of the ship (as shown in FIGS. 1 and 2) would tendto turn or steer the ship to the right (or left). This ability to useforces from the aerial wing 120 to turn or steer the ship may beadvantageous. In particular, if a tight turning radius is required or ifthe rudder or steering mechanism onboard the ship is not workingproperly, then the aerial vehicle could be used to turn or steer theship. Furthermore, if there was a need to turn the ship quickly, theaerial vehicle could be used to turn the ship more quickly and with asmaller turning radius than using only the marine propeller propulsionsystem on the ship. In some embodiments the aerial wing could fly indirection having a component vector opposite of the movement of theship, and even against the wind, to perform the steering or turningfunctions. For example, the aerial wing may fly between at an angle of45 and 135 degrees from the longitudinal axis or the ship to effect asteering or turning maneuver in certain applications.

In some applications, it may be possible to include two or more aerialvehicles to provide more pulling force than a single aerial vehicle.

Illustrative Ocean-Going Vessels

FIG. 8A is a simplified illustration of an ocean-going vessel 300,according to an example embodiment. As shown, the ocean-going vessel 300includes an electrodialysis system 302, an electrolysis system 304, arefinery system 306, an AWT 308, and a fuel storage container 310.

In the illustrated example, the ocean-going vessel 300 is a ship. Assuch, ocean-going vessel 300 may include one or more electric- orgas-powered propulsion systems (e.g., engines coupled to submergedpropellers) that are typical of ships. Other types of propulsion systemsare also possible. Alternatively, ocean-going vessel 300 could be asailboat. Further, ocean-going vessel 300 may be implemented on varioustypes of ships, which may have various types of hulls, and which mayhave a different number of hulls (e.g., a single-hull, a catamaran, atrimaran, etc.).

FIG. 10 is a flow chart illustrating a process that may be implementedby one or more control systems on an ocean-going vessel that includes anAWT, according to an example embodiment. As shown, method 400 involvesoperating at least one AWT to convert wind energy to electrical energy,such that the AWT provides power to at least one of an electrolysissystem and an electrodialysis system for at least some period of time,where both the electrodialysis system and the electrolysis system aredisposed on an ocean-going vessel, as shown by block 402. Further,method 400 involves operating the electrodialysis system to extractcarbon dioxide (CO₂) gas from seawater, and operating the electrolysissystem to apply electrolysis to seawater to produce hydrogen (H₂) gas,as shown by blocks 404 and 406, respectively. Yet further, method 400involves operating a refinery system to: (a) receive both the H₂ gasproduced by electrolysis system and the CO₂ gas extracted by theelectrodialysis system and (b) process a mixture of the H₂ gas and theCO₂ gas to produce a fuel or chemical, as shown by block 408.

A. Electrodialysis Systems

Referring again to FIG. 8A, in an example embodiment, ocean-going vessel300 includes an electrodialysis system 302, which is configured toextract carbon dioxide (CO₂) from seawater that passes through one ormore membranes of the electrodialysis system 302. The CO₂ that isproduced can then be supplied to the refinery system 306.

Further, once a BPMED system removes the dissolved CO₂ from theacidified seawater, the acidified seawater can be combined with thebasified seawater. Combining the stripped and acidified seawater withthe basified seawater may neutralize the pH of the resulting solution,such that it can be safely output into the ocean.

In some embodiments, an ocean-going vessel 300 may include a system thatuses fractional distillation of water to separate CO₂ from otherabsorbed gases. Other techniques for extracting CO₂ from seawater arealso possible. In general, it is contemplated that an ocean-going vessel300 may use any feasible technique and/or system for extracting CO₂ fromseawater

In a further aspect, an intake 320 is arranged such that movement of thevessel through water forces seawater to flow into the electrodialysissystem 302. In the illustrated configuration, the intake 320 includes anangled feature 316. The angled feature extends from the bottom of thevessel 300, such that when the vessel moves through water (e.g., in thegeneral direction indicated by arrow 312), water is forced to flowthrough the intake 320 into electrodialysis system 302, as indicated byarrow 314. This intake configuration may be beneficial as it uses themotion of the vessel through the water to provide the energy needed tomove seawater to the electrodialysis system 302, and thus may alleviatethe need to use an electric or fuel-powered pump to supply seawater toand/or move seawater through the electrodialysis system 302.

It should be understood that intake 320 is just one example of astructural design that forces water into the electrodialysis system 302,and thus alleviates or reduces the need for a pump. It is contemplatedthat other structural designs providing similar functionality may beutilized. Further, it is possible that an ocean-going vessel may utilizeone or more pumps to supply seawater to and/or move seawater through theelectrodialysis system 302, instead of or in addition to using astructural design that forces water to the electrodialysis system 302.

As one additional example, in some embodiments, the intake to theelectrodialysis system 302 and/or to the electrolysis system 304 mayinclude an impeller through which water flows before entering theelectrodialysis system 302 and/or to the electrolysis system 304. Assuch, when the vessel moves forward the forward motion of the vesselcreates a pressure gradient that pulls water through the intake andspins the impeller, thus increasing the pressure of water flowing intothe electrodialysis system 302 and/or into the electrolysis system 304.

B. Electrolysis Systems

In an example embodiment, ocean-going vessel 300 includes anelectrolysis system 304, which is configured to apply electrolysis toseawater to produce hydrogen (H₂). In particular, the electrolysissystem 304 takes in and processes seawater in order to produce CO₂H₂gas; e.g., by applying a current to water to drive the followingreaction: 2H₂0→2H₂+O₂.

The H₂ gas that is produced by electrolysis system 304 can then besupplied to the refinery system 306 for production of fuels orchemicals. Further, the oxygen (O₂) gas that is produced by theelectrolysis system 304 may be vented into the atmosphere or used forsome other purpose.

In a further aspect, an intake 322 is arranged such that movement of thevessel through water forces seawater to flow into the electrolysissystem 304. In the illustrated configuration, the intake 322 includes anangled feature 318, which functions similarly to the angled feature 316of intake 320. As such, when the vessel moves through water (e.g., inthe general direction indicated by arrow 312), water is forced to flowthrough intake 322 into electrolysis system 304, as indicated by arrow315.

It should be understood that intake 322 is just one example of astructural design that forces water into the electrolysis system 304 andthus alleviates the need for a pump to do so. It is contemplated thatother structural designs providing similar functionality may beutilized. Further, it is possible that an ocean-going vessel may utilizeone or more pumps to supply seawater to and/or move seawater through theelectrolysis system 304, instead of or in addition to using a structuraldesign that forces water to the electrolysis system 304.

C. Illustrative Airborne Wind Turbines

As noted above, ocean-going vessel 300 includes an AWT 308, which isoperable generate electrical energy for the vessel. As such, the AWT 308may be utilized to generate power for the electrolysis system 304, theelectrodialysis system 302, and/or other components or systems on theocean-going vessel 300. The AWT 308 may take a form and operate asdescribed in reference to FIGS. 1-3, 5, 6, and 7A-7B, or may takeanother form and/or may operate in a different manner.

As described above, an AWT such as AWT 308 may be configured to operatein a hover-flight mode, as well as in a flying mode or powered flyingmode. In a further aspect of some embodiments, an AWT 308 may beconfigured to operate in a vessel-steering mode. In such an embodiment,the AWT 308 may fly so as to steer and/or pull the ocean-going vessel300.

For example, FIG. 8B is an illustration showing an AWT 358 operating ina vessel-steering mode. As shown, in the vessel steering mode, theaerial vehicle 360 may be positioned for forward flight in the directionindicated by arrow 362. (Note that “forward flight” should be understoodto mean that at least a component of the vehicle's trajectory is in theforward direction.) Thus, the aerial vehicle may use its propulsionsystem (e.g., its rotors, which also function as wind turbines when inpower generation mode) to create a thrust vector having a horizontalcomponent as indicated by arrow 362, such that it tows the ocean-goingvessel 350 via tether 352.

In some embodiments, the aerial vehicle 360 may be configured to tow theocean-going vessel 350 in a desired direction. To do so, the aerialvehicle 360 may maneuver such that its thrust vector has a horizontalcomponent in the direction in which it is desired for the vessel totravel. Doing so may cause the vessel 350 to turn until the vessel istravelling in the direction of the horizontal component of the aerialvehicle's thrust vector.

In a further aspect, an aerial vehicle may be operable to tow the vessel350 in order to assist the vessel in turning. For example, if theocean-going vessel 350 is using its own propulsion and steering systemsto turn to the right or the left, the aerial vehicle may operate inforward-flight mode and turn right or left such that the horizontalcomponent of its thrust vector is angled to the right or left of thevessel's current direction of travel. Doing so may thus help theocean-going vessel 350 to turn more quickly than it otherwise could, ifonly using its other propulsion systems.

In some embodiments, the aerial vehicle 360 may be configured to tow theocean-going vessel 350 in a desired direction, while at the same timeoperating in a power generation mode. For example, a route may be chosenwhich provides mostly down-wind travel for high efficiency. Inparticular, while aerial vehicle 360 is in crosswind-flight, there maybe a horizontal component of the force that the aerial vehicle 360exerts on the vessel 350. The vessel 350 may further include a keeland/or a rudder (or other features), that can help to steer the vesselwhen the horizontal component of the force that the aerial vehicle 360exerts on the vessel differs from the desired direction of travel.Essentially, the aerial vehicle may operate in a similar manner as atraditional sail does, in conjunction with a keel and/or a rudder (orother features), in order to steer vessel 350.

D. Illustrative Power Systems

Referring back to FIG. 8A, in an exemplary embodiment, some or all ofthe energy that used to power the electrolysis system 304 may beprovided by the AWT 308. Accordingly, the ground station of the AWT maybe electrically connected to the electrolysis system, such thatelectrical power that is generated by airflow rotating the rotors of theaerial vehicle 330 can be relayed to the electrolysis system 304 via thetether 332, ground station 334, and an electrical connection 336.Provided with this electricity source, the electrolysis system 304 canthen apply a current to water to perform electrolysis. Further, notethat while electrical connections between the AWT 308 and othercomponents of the ocean-going vessel are not shown in FIG. 8A, the AWT308 may also be electrically coupled to other components, such aselectrodialysis system 302, in order to provide generated electricalpower to such components.

In some embodiments, other energy sources may be used to supplement thepower provided by AWT 308. For example, ocean-going vessel 300 mayutilize one or more other renewable or “green” energy sources, such as asolar energy generation system (e.g., solar cells), a bio-fuel energygeneration system, and/or a synthetic fuel energy generation system,among other possibilities. An ocean-going vessel 300 could additionallyor alternatively utilize a low carbon power generation method tosupplement the AWT 308, such as by including a nuclear power system thatgenerates electricity for the vessel. Further, in some embodiments,ocean-going vessel 300 could also utilize one or more non-renewablesources energy sources, such as by using an internal combustion engineand/or other types of energy generation systems that burn a fossil fuel.(Preferably, however, the ocean-going vessel 300 is designed so as tominimize and hopefully eliminate use of such fossil fuels.)

In some scenarios, the ocean-going vessel 300 may even be configured topower its systems using some of the fuel that has been stored fuelstorage container 310, which was previously produced by its refinerysystem 306. For example, there might be scenario where there is anextended period of without winds that are suitable for electrical powergeneration by the AWT, and/or where conditions are such that other greenenergy sources are not able to generate adequate amounts of energy topower the ocean-going vessel 300. In such a scenario, the ocean-goingvessel 300 might utilize some of the fuel that the refinery system 306has produced and stored in fuel storage container 310 in order that thevessel can continue operation until winds are again conducive forelectrical power generation by the AWT and/or until conditions are suchthat another green power generation system can again be utilized topower the vessel.

E. Illustrative Refinery Systems

In an example embodiment, ocean-going vessel 300 includes at least onerefinery system 306. The refinery system 306 is operable to use both theH₂ produced by electrolysis system 304 and the CO₂ extracted by theelectrodialysis system 306 to produce at least one type of fuel orpetrochemical. Further, in some embodiments, an ocean-going vessel 300may include multiple refinery systems, such that the vessel is capableof producing multiple types of fuels or petrochemicals. It is alsopossible that a single refinery system may be operable to produce anumber of different types of fuels or petrochemicals. In embodiments,where an ocean-going vessel 300 is capable of producing two or moredifferent types of fuels or petrochemicals, the vessel may includemultiple storage containers 310, such that the each fuel orpetrochemical can be stored in a separate container.

Various types of refinery systems, which produce various fuels orpetrochemicals from the inputs of hydrogen (H₂) and carbon dioxide(CO₂), are currently known in the art. Further, there is much interestin developing new and more efficient processes for producing fuel fromrenewable inputs such as hydrogen (H₂) and carbon dioxide (CO₂) (andfrom CO₂ in particular, due to the urgent need to prevent furtherincrease, and hopefully decrease, the amount of CO₂ in the atmosphereand oceans).

Some examples of processes that may be used by a refinery system 306will now be described. In some embodiments, refinery system 306 may usea number of catalyzed syngas reactions to selectively produce ethanoldirectly from CO₂ and H₂. In some cases, CO₂ and H₂ may be used tocreate methanol, which may then be used to create ethanol. However, itshould be understood that these examples are provided for explanatorypurposes, and are not intended to be limited. It is contemplated that anocean-going vessel's refinery system could potentially utilize anyprocess that is currently known or later developed for fuel or chemicalproduction using H₂ and CO₂ as inputs.

In some embodiments, a refinery system 306 may include or take the formof a Fischer-Tropsch reactor, which utilizes a Fischer-Tropsch processto produce a liquid hydrocarbon. A typical Fischer-Tropsch processinvolves a sequence of chemical reactions that produces a liquidhydrocarbon from a mixture of carbon monoxide (CO) and hydrogen (H₂)gases (a mixture that may also be referred to as “syngas”). Forinstance, a number of useful hydrocarbons following the formula ofC_(n)H_((2n+2)) may be produced using Fischer-Tropsch processes. Inparticular, various Fischer-Tropsch processes may produce suchhydrocarbons via reactions that follow the formula of:(2n+1)+H₂+nCO→C_(n)H_((2n+2))+nH₂O.

Since a typical Fischer-Tropsch process utilizes carbon monoxide (CO) asan input, a refinery system 306 may be configured to produce CO from theCO₂ that is supplied by electrodialysis system 302. For example,refinery system 306 may implement a reverse water gas shift process thattakes H₂ and CO₂ gases as inputs and produces carbon monoxide and wateras follows: 11CO₂+11H₂→11CO+11H₂O. Other examples are also possible. Thecarbon monoxide that is produced from such a process may then be used ina Fischer-Tropsch process. Further, the ocean-going vessel 300 mayrelease the water that is produced in the reverse water gas shiftprocess back into the ocean, and/or use this water for other purposes.

In an exemplary embodiment, a Fischer-Tropsch process may be used toproduce a synthetic fuel (also referred to as a “synfuel”) from syngas.The refinery system 306 may be further configured to process some or allof the synthetic fuel to convert the synthetic fuel into ethanol. Forexample, the refinery system 306 may use syngas fermentation, which is amicrobial process where certain microorganisms, such as variousacetogens, are used to produce ethanol and other chemicals via syngasutilization.

In some embodiments, a refinery system 306 could utilize aFischer-Tropsch process to produce synthetic jet fuel (e.g., C₁₁H₂₄) ora synthetic diesel fuel, which may then be stored in anappropriately-designed fuel storage container 310. For example, H₂ andCO₂ may be used by the refinery as inputs to a reverse water gas shiftprocess that produces carbon monoxide and water as described above. Thefollowing Fischer-Tropsch process may then be applied to convert amixture of the carbon monoxide and hydrogen into a liquid jet fuel andoxygen gas as follows: 11CO₂+12H₂O→C₁₁H₂₄+17O₂.

Other types of Fischer-Tropsch processes may be implemented by anexample refinery system 306. Additionally or alternatively, a refinerysystem may implement processes other than Fischer-Tropsch processes,which utilize H₂ and CO₂ to produce ethanol and/or other fuels and/orchemicals.

Example Method of Pulling a Vehicle With an Aerial Wind Turbine System

FIG. 9 shows a method 700 that may be used for pulling a vehicle with anaerial wind turbine system. Method 700 includes the step 702 ofproviding an aerial wing with a fuselage attached to the aerial wing,and a plurality of rotors each having a plurality of rotatable bladespositioned on the aerial wing, and having an electrically conductivetether having a first end secured to the aerial wing and a second endsecured to a ground station positioned on a vehicle, wherein the aerialwing is adapted to receive electrical power from the vehicle that isdelivered to the aerial wing through the electrically conductive tether;wherein the aerial wing is adapted to operate in a flying mode toharness wind energy to provide a first pulling force through the tetherto pull the vehicle; and wherein the aerial wing is also adapted tooperate in a powered flying mode wherein the rotors may be powered sothat the turbine blades serve as thrust-generating propellers to providea second pulling force through the tether to pull the vehicle, and thestep 704 of operating the aerial wing in the powered flying mode toprovide a pulling force through the tether to pull the vehicle.

Method 700 may further optionally include the step of including the stepof operating the aerial wing in power generation mode during the poweredflying mode where air moving across the rotatable blades of one or moreof the rotors forces them to rotate, thereby driving a generator toproduce electrical energy.

The present embodiments may be used to provide a pulling force to pullthe ship by operating the aerial wing in flying mode or powered flyingmode, while at the same time operating the aerial wing in powergeneration mode, wherein the generated power may be used to power anelectrolysis system or an electrodialysis system located on board theship. The electrodialysis system may then be used to extract carbondioxide (CO₂) gas from seawater, and the electrolysis system may be usedto apply electrolysis to seawater to produce hydrogen (H₂). A furtherprocess may be used to process a mixture of the H₂ gas and the CO₂ gasto produce a fuel or chemical.

Conclusion

The above detailed description describes various features and functionsof the disclosed systems, devices, and methods with reference to theaccompanying figures. While various aspects and embodiments have beendisclosed herein, other aspects and embodiments will be apparent tothose skilled in the art. The various aspects and embodiments disclosedherein are for purposes of illustration and are not intended to belimiting, with the true scope and spirit being indicated by thefollowing claims.

What is claimed is:
 1. A vehicle-based airborne wind turbine system,comprising: an aerial wing; a plurality of rotors each having aplurality of rotatable blades positioned on the aerial wing; anelectrically conductive tether having a first end secured to the aerialwing and a second end secured to a ground station positioned on avehicle; wherein the aerial wing is adapted to receive electrical powerfrom the vehicle that is delivered to the aerial wing through theelectrically conductive tether; wherein the aerial wing is adapted to(i) operate in a flying mode to harness wind energy to provide a firstpulling force through the tether to pull the vehicle; and (ii) operatein a powered flying mode wherein the rotors may be powered so that therotatable blades serve as thrust-generating propellers to provide asecond pulling force through the tether to pull the vehicle; and thesystem further including: an electrodialysis system arranged on thevehicle and configured to extract carbon dioxide (C0₂) from seawater; anelectrolysis system arranged on the vehicle and configured to applyelectrolysis to seawater to produce hydrogen (H₂); a refinery systemconfigured to use both the H₂ produced by electrolysis system and theC0₂ extracted by the electrodialysis system to produce a fuel orchemical; and further including a water intake positioned on a bottom ofthe vehicle.
 2. The system of claim 1, wherein when the aerial wing isoperated in the powered flying mode, the rotors are powered byelectrical power that is delivered from the vehicle through theelectrically conductive tether.
 3. The system of claim 1, wherein theaerial wing is also adapted to operate in a power generation mode duringthe flying mode where air moving across the rotatable blades of one ormore of the rotors forces them to rotate, thereby driving a generator toproduce electrical energy.
 4. The system of claim 3, wherein at leastsome of the electrical energy produced during the power generation modeis delivered through the electrically conductive tether to the vehicle.5. The system of claim 1, wherein the aerial wing provides a pullingforce on the vehicle while in the flying mode or in the powered flyingmode.
 6. The system of claim 3, wherein the aerial wing is adapted tooperate in the powered flying mode and the power generation mode at thesame time, by operating one or more of the rotors so that the rotatableblades serve as thrust-generating propellers, and by operating one ormore of the rotors in the power generation mode.
 7. The system of claim1, wherein the refinery system is configured to: use both the H₂produced by electrolysis system and the C0₂ extracted by theelectrodialysis system to produce a synthetic fuel; and convert at leastsome of the synthetic fuel into ethanol.
 8. The system of claim 1,further comprising: a rotatable drum positioned with the ground station;wherein rotation of the drum causes the tether to be wrapped around thedrum causing the aerial wing to be reeled in towards the ground station;and wherein the tether may be reeled out from the rotatable drum whenthe aerial wing ascends.
 9. The system of claim 8, further comprising:an aerial wing perch positioned with the ground station; wherein theaerial wing is adapted to be parked on the aerial wing perch.
 10. Thesystem of claim 9, wherein the aerial wing is adapted to fly in a hovermode where a fuselage that is attached to the aerial wing is generallyperpendicular to horizontal when the aerial wing is approaching ordeparting the aerial wing perch.
 11. An airborne wind turbine system,comprising: an aerial wing; a plurality of rotors each having aplurality of rotatable blades positioned on the aerial wing; anelectrically conductive tether having a first end secured to the aerialwing and a second end secured to a ground station positionable on avehicle; wherein the aerial wing is adapted to receive electrical powerfrom the vehicle that is delivered to the aerial wing through theelectrically conductive tether; wherein the aerial wing is adapted to(i) operate in a flying mode to harness wind energy to provide a firstpulling force through the tether to pull the vehicle; and (ii) operatein a powered flying mode wherein the rotors may be powered so that therotatable blades serve as thrust-generating propellers to provide asecond pulling force through the tether to pull the vehicle; and thesystem further including: an electrodialysis system arranged on thevehicle and configured to extract carbon dioxide (C0₂) from seawater; anelectrolysis system arranged on the vehicle and configured to applyelectrolysis to seawater to produce hydrogen (H₂); a refinery systemconfigured to use both the H₂ produced by electrolysis system and theC0₂ extracted by the electrodialysis system to produce a fuel orchemical; and further includes a water intake positioned on a bottom ofthe vehicle.
 12. The system of claim 11, wherein the aerial wing is alsoadapted to operate in a power generation mode during the flying modewhere air moving across the rotatable blades of one or more of therotors forces them to rotate, thereby driving a generator to produceelectrical energy.
 13. The system of claim 12, wherein the aerial wingis adapted to operate in the powered flight mode and the powergeneration mode at the same time, by operating one or more of the rotorsso that the rotatable blades serve as thrust-generating propellers, andby operating one or more of the rotors in the power generation mode. 14.A method of pulling a vehicle, comprising the steps of: providing anaerial wing with a plurality of rotors each having a plurality ofrotatable blades positioned on the aerial wing, and having anelectrically conductive tether having a first end secured to the aerialwing and a second end secured to a ground station positioned on avehicle, wherein the aerial wing is adapted to receive electrical powerfrom the vehicle that is delivered to the aerial wing through theelectrically conductive tether; wherein the aerial wing is adapted tooperate in a flying mode to harness wind energy to provide a firstpulling force through the tether to pull the vehicle; and wherein theaerial wing is also adapted to operate in a powered flying mode whereinthe one or more of the rotors are powered so that the rotatable bladesserve as thrust-generating propellers to provide a second pulling forcethrough the tether to pull the vehicle; operating the aerial wing in thepowered flying mode to provide the second pulling force through thetether to pull the vehicle; operating an electrodialysis system arrangedon the vehicle to extract carbon dioxide (C0₂) from seawater; operatingan electrolysis system arranged on the vehicle to apply electrolysis toseawater to produce hydrogen (H₂); operating a refinery system arrangedon the vehicle to use both the H₂ produced by the electrolysis systemand the C0₂ extracted by the electrodialysis system to produce a fuel orchemical; and further including a water intake positioned on a bottom ofthe vehicle.
 15. The method of claim 14, further including the step ofoperating the aerial wing in a power generation mode during the poweredflying mode where air moving across the rotatable blades of one or moreof the rotors forces them to rotate, thereby driving a generator toproduce electrical energy.
 16. The method of claim 15, further includingthe step of delivering at least some of the electrical energy producedduring the power generation mode through the electrically conductivetether to the vehicle.
 17. The method of claim 14, further including thestep of operating the aerial wing in power generation mode during thepowered flying mode, by operating one or more of the rotors so that therotatable blades serve as thrust-generating propellers, and by operatingone or more of the rotors in the power generation mode where air movingacross the rotatable blades of one or more of the rotors forces them torotate, thereby driving a generator to produce electrical energy. 18.The method of claim 14, further including a rotatable drum positionedwith the ground station wherein rotation of the drum causes the tetherto be wrapped around the drum causing the aerial wing to be reeled intowards the ground station, wherein the tether may be reeled out fromthe rotatable drum when the aerial wing ascends, and an aerial wingperch positioned with the ground station wherein the aerial wing isadapted to be parked on the aerial wing perch.
 19. The method of claim18, further including the step of operating the aerial wing in a hovermode where a fuselage that is attached to the aerial wing is generallyperpendicular to horizontal when the aerial wing is approaching theaerial wing perch.
 20. The method of claim 18, further including thestep of operating the aerial wing in a hover mode where a fuselage thatis attached to the aerial wing is generally perpendicular to horizontalwhen the aerial wing is departing the aerial wing perch.
 21. The methodof claim 14, further including the step of operating the aerial wing inpowered flying mode at an angle from a longitudinal axis of the vehicleto steer or turn the vehicle.
 22. The method of claim 21, wherein theangle is between 45 and 135 degrees.
 23. The method of claim 14, furtherincluding the step of operating the refinery system to use both the H₂produced by the electrolysis system and the C0₂ extracted by theelectrodialysis system to produce a synthetic fuel.
 24. The method ofclaim 23, further including the step of converting at least some of thesynthetic fuel into ethanol.
 25. The system of claim 1, wherein thewater intake is adapted to provide a flow of water to theelectrodialysis system.
 26. The system of claim 1, wherein the waterintake is adapted to provide a flow of water to the electrolysis system.27. The system of claim 25, further including an additional water intakeadapted to provide a flow of water to the electrolysis system.